title: Optimal time interval between a single course of antenatal corticosteroids and delivery for reduction of respiratory distress syndrome in preterm twins.
abstract: OBJECTIVE
  The objective of the study was to investigate the effect of a single course of antenatal corticosteroid (ACS) therapy on the incidence of respiratory distress syndrome (RDS) in preterm twins according to the time interval between ACS administration and delivery.
  
  
  METHODS
  We performed a retrospective cohort study of twins born between 24 and 34 weeks of gestation from November 1995 to May 2011. Subjects were grouped on the basis of the time interval between the first ACS dose and delivery: the ACS-to-delivery interval of less than 2 days (n = 166), 2-7 days (n = 114), and more than 7 days (n = 66). Pregnancy and neonatal outcomes of each group were compared with a control group of twins who were not exposed to ACS (n = 122). Multiple logistic regression analysis was used to examine the association between the ACS-to-delivery interval and the incidence of RDS after adjusting for potential confounding variables.
  
  
  RESULTS
  Compared with the ACS nonexposure group, the incidence of RDS in the group with an ACS-to-delivery interval of less than 2 days was not significantly different (adjusted odds ratio [aOR], 1.089; 95% confidence interval [CI], 0.524-2.262; P = .819). RDS occurred significantly less frequently when the ACS-to-delivery interval was between 2 and 7 days (aOR, 0.419; 95% CI, 0.181-0.968; P = .042). However, there was no significant reduction in the incidence of RDS when the ACS-to-delivery interval exceeded 7 days (aOR, 2.205; 95% CI, 0.773-6.292; P = .139).
  
  
  CONCLUSIONS
  In twin pregnancies, a single course of ACS treatment was associated with a decreased rate of RDS only when the ACS-to-delivery interval was between 2 and 7 days.
authors.affiliation: Department of Obstetrics and Gynecology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea.
authors.forename: Jin-Yi
authors.initials: JY
authors.lastname: Kuk
authors.forename: Jung-Ju
authors.initials: JJ
authors.lastname: An
authors.forename: Hyun-Hwa
authors.initials: HH
authors.lastname: Cha
authors.forename: Suk-Joo
authors.initials: SJ
authors.lastname: Choi
authors.forename: Juan E
authors.initials: JE
authors.lastname: Vargas
authors.forename: Soo-young
authors.initials: SY
authors.lastname: Oh
authors.forename: Cheong-Rae
authors.initials: CR
authors.lastname: Roh
authors.forename: Jong-Hwa
authors.initials: JH
authors.lastname: Kim
mesh_terms: D000305:Adrenal Cortex Hormones / Q000008:administration & dosage*; D000328:Adult; D015331:Cohort Studies; D036861:Delivery, Obstetric; D005260:Female; D006801:Humans; D007231:Infant, Newborn; D007234:Infant, Premature; D016015:Logistic Models; D011247:Pregnancy; D012127:Respiratory Distress Syndrome, Newborn / Q000517:prevention & control*; D012189:Retrospective Studies; D013997:Time Factors; D014427:Twins
chemical_list: D000305:Adrenal Cortex Hormones
keywords: antenatal corticosteroids; preterm delivery; respiratory distress syndrome; steroid-to-delivery interval; twin pregnancy